Dark-Energy Camera Starts Taking Pictures

The latest, greatest hunt for dark energy has begun, with a massive camera installed on a Chilean mountaintop returning the first of millions of photographs that should help astronomers learn more about the strange forces driving our universe's evolution.

"It works like other digital cameras, only it's much larger, much more sensitive, and mounted on a large telescope," said astronomer Josh Frieman of the University of Chicago, the Dark Energy Survey's director.

"We're using it to get a much better measurement of cosmic expansion in the universe," Frieman continued. "We're going to measure the evolution of structure in the universe. And the way to do both those things is to do a really big survey of the sky."

Over the next five years, the camera, set inside the Blanco telescope in the arid mountains of Chile's high-altitude Atacama desert, where stars shine with a clarity seen in few other places on Earth, will photograph no fewer than 300 million galaxies.

After categorizing those galaxies according to age, form and distance from Earth -- the camera is sensitive enough to detect light emitted 8 billion light years away -- astronomers should better understand how galaxies swirl and cluster over deep time, and also how the universe expands.

In the 1990s, images from the Hubble telescope showed astronomers that the universe, which had been thought to expand at a steady speed, is actually expanding at an ever-accelerating rate. Dark energy was the name given to the hypothetical force that must drive that strange acceleration.

On the following pages, Wired looks at some of the Dark Energy Survey's first pictures.

Above:

Fornax Cluster Detail

Detail of Dark Energy Camera image of the barred spiral galaxy NGC 1365, part of the Fornax cluster of galaxies.

Fornax Mosaic

Full mosaic image of the Fornax cluster of galaxies, which lies about 60 million light years from Earth.

"We're not studying the galaxies themselves, but using galaxies as tracers of the structure of the universe," Frieman said.

47 Tucanae Detail

Mosaic detail from photographs of the center of the globular star cluster 47 Tucanae, a mere 17,000 light years from Earth. The Dark Energy Camera will ultimately detect galaxies some 8 billion light years away.

"This is a relatively nearby cluster, and we'll eventually be counting 100,000 clusters like this," said Frieman.

Small Magellanic Cloud Mosaic

Full mosaic image of the Small Magellanic Cloud, which is about 200,000 light years from Earth. To make sure the Dark Energy Camera is working properly, the first photographs were taken of well-known galaxies -- Frieman called them "famous bright things" -- which astronomers can use as baseline reference images.